The invention relates to isolated nucleic acids and polypeptides derived from Candida albicans that are useful as molecular targets for diagnostics, prophylaxis and treatment of pathological conditions, as well as materials and methods for the diagnosis, prevention, and amelioration of pathological conditions resulting from fungal infection.
Incorporated herein by reference in its entirety is a Sequence Listing comprising SEQ ID No. 1 to SEQ ID NO:28208. The Sequence Listing is contained on a CD-ROM, three copies of which are filed, the Sequence Listing being in a computer-readable ASCII file named xe2x80x9ccand09.2001.txtxe2x80x9d, created on Sep. 14, 2001 and of 38,660 bytes in size, in IBM-PC Windows(copyright)NT v4.0 format.
Candida albicans is a dimorphic fungus which has both a yeast-like growth habit and a filamentous form consisting of both hyphae and pseudohypae. The fungus is a member of the normal surface flora of most individuals. Although no sexual state has been described for C. albicans, the genome is diploid in most strains (Whelan, W L et al. (1980) Mol. Gen. Genet. 180: 107-113; Whelan, W L and Magee, P T (1981) J. Bacteriol. 145: 896-903; Poulter, R. (1982) J. Bacteriol. 152: 969-975) and rearranges relatively frequently (Rustchenko-Bulgac E P, et al (1990) J Bacteriol. 172: 1276-1283; Barton, R C and Scherer, S (1994)J. Bacteriol . 176: 756-763). In addition, one non-universal decoding is known in which a leucine codon (CUG) is translated as a serine (Leuker et al. (1994), Mol. Gen. Genet. 245: 212-217; Santos et al., (1993) EMBO Journal 12:607-616). This creates difficulties in the application of the powerful genetic and molecular methods used in Saccharomyces and Schizosaccharomyces.
C. albicans exists as part of the normal microbial flora in humans, but can produce opportunistic infections ranging from topical infections such as oral thrush to life-threatening disseminated mycoses (Ampel, N M (1996) Emerg. Infect. Dis. 2: 109-116). Candida is a major cause of nosocomial infections and was found to account for more than 75% of all fungal nosocomial infections reported by NNIS (National Nosocomial Infections Surveillance) hospitals from 1980-1990 in which fungi alone accounted for 7.9% of all nosocomial infections (Beck-Sagu, C M and Jarvis, W R (1993) J. Infect. Dis. 167: 1247-1251). Although the source of Candida in infections is frequently traced to endogenous sources on the patient, it has also been traced to exogenous sources in the hospital environment including contaminated solutions and equipment (Shetertz, R J et al. (1992) J. Pediatr. 120: 455-461; Weems, J J et al. (1987) J. Clin. Microbiol. 1925: 1029-1032), and health care workers (Hunter, P R et al (1990) J. Med Vet Mycol. 28: 317-325; Burnie, J P (1986) J. Hosp. Infect. 8: 1-4; Doebbeling, B N et al. (1991) J. Clin. Microbiol. 29: 1268-1270). Numerous investigations into the molecular basis of pathogenicity have been made implicating the hyphal form (Lo, H J et al. (1997) Cell 90:939-949), surface molecules including adhesins (Fukazawa Y and Kagaya K (1997)J Med Vet Mycol 35:87-99), and ATP-binding cassette-containing multi-drug resistance proteins (Prasad, R et al.(1995) Curr. Genet. 27: 320-329).
The antimicrobials currently in use against Candida are generally of three types: azoles, such as iluconazole, itraconazole, and clotrimazole; polyenes, such as amphotericin B and nystatin; and 5-fluorocytosine. However, invasive infections are treated primarily with fluconazole, amphotericin B, and 5-fluorocytosine, although the latter two compounds have significant toxic side effects. The development of resistance to iluconazole by C. albicans has been noted by a number of researchers (Redding, S (1994) Clin. Infect. Dis. 18: 339-346; Sargeorzan, J A (1994) Am. J. Med. 97: 339-346; Revankar, S G et al. (1996) J. Infect. Dis. 174: 821-827; Marr, K A et al. (1997) Clin. Infect. Dis 25: 908-910). Relatively short treatments seem to result in few if any resistant isolates, but extended treatments including prophylactic treatments such as are required among immunocompromised and AIDS patients, result in the appearance of fluconazole-resistant strains (Johnson, E M (1995) J. Antimicrob. Chemother. 35: 103-114). Development of fluconazole-resistance has been observed to be associated with the development of amphotericin-resistance (Vazquez, J A (1996) Antimicrob. Agents Chemother. 40: 2511-2516; Nolte, F S et al. (1997) Antimicrob. Agents Chemother. 41: 196-199; White, T C (1997) ASM News 63: 427-433) consistent with the action of both drugs on ergosterol in the membrane.
The difficulty in diagnosing C. albicans infections, the limited spectrum of current therapeutic drugs and the development of drug resistant strains of C. albicans provide the rationale for the identification of targets for more rapid and effective methods of identification, prevention, and treatment of candidiasis. The elucidation of the genome of C. albicans would enhance the understanding of how C. albicans, as well as other fungi, causes invasive disease and how best to combat fungal infection.
The present invention fulfills the need for diagnostic tools and therapeutics by providing fungal-specific compositions and methods for detecting, treating, and preventing fungal infection, in particular C. albicans infection. They also have use as biocontrol agents for plants.
The present invention encompasses isolated nucleic acids and polypeptides derived from C. albicans that are useful as reagents for diagnosis of fungal disease, components of effective antifungal vaccines, and/or as targets for antifungal drugs including anti-C. albicans drugs. They can also be used to detect the presence of C. albicans and other Candida species in a sample; and in screening compounds for the ability to interfere with the C. albicans life cycle or to inhibit C. albicans infection.
More specifically, this invention features compositions of nucleic acids corresponding to entire coding sequences of C. albicans proteins, including surface or secreted proteins or parts thereof, nucleic acids capable of binding mRNA from C. albicans proteins to block protein translation, and methods for producing C. albicans proteins or parts thereof using peptide synthesis and recombinant DNA techniques. This invention also features antibodies and nucleic acids useful as probes to detect C. albicans infection. In addition, vaccine compositions and methods for the protection or treatment of infection by C. albicans are within the scope of this invention.
The nucleotide sequences provided in SEQ ID NO: 1-SEQ ID NO: 14103, a fragment thereof, or a nucleotide sequence at least about 99.5% identical to a sequence contained within SEQ ID NO: 1-SEQ ID NO: 14103 may be xe2x80x9cprovidedxe2x80x9d in a variety of medias to facilitate use thereof. As used herein, xe2x80x9cprovidedxe2x80x9d refers to a manufacture, other than an isolated nucleic acid molecule, which contains a nucleotide sequence of the present invention, i.e., the nucleotide sequence provided in SEQ ID NO: 1-SEQ ID NO: 14103, a fragment thereof, or a nucleotide sequence at least about 99.5% identical to a sequence contained within SEQ ID NO: 1-SEQ ID NO: 14103. Uses for and methods for providing nucleotide sequences in a variety of media is well known in the art (see e.g., EPO Publication No. EP 0 756 006).
In one application of this embodiment, a nucleotide sequence of the present invention can be recorded on computer readable media. As used herein, xe2x80x9ccomputer readable mediaxe2x80x9d refers to any media which can be read and accessed directly by a computer. Such media include, but are not limited to: magnetic storage media, such as floppy discs, hard disc storage media, and magnetic tape; optical storage media such as CD-ROM; electrical storage media such as RAM and ROM; and hybrids of these categories such as magnetic/optical storage media. A person skilled in the art can readily appreciate how any of the presently known computer readable media can be used to create a manufacture comprising computer readable media having recorded thereon a nucleotide sequence of the present invention.
As used herein, xe2x80x9crecordedxe2x80x9d refers to a process for storing information on computer readable media. A person skilled in the art can readily adopt any of the presently known methods for recording information on computer readable media to generate manufactures comprising the nucleotide sequence information of the present invention.
A variety of data storage structures are available to a person skilled in the art for creating a computer readable media having recorded thereon a nucleotide sequence of the present invention. The choice of the data storage structure will generally be based on the means chosen to access the stored information. In addition, a variety of data processor programs and formats can be used to store the nucleotide sequence information of the present invention on computer readable media. The sequence information can be represented in a word processing text file, formatted in commercially-available software such as WordPerfect and Microsoft Word, or represented in the form of an ASCII file, stored in a database application, such as DB2, Sybase, Oracle, or the like. A person skilled in the art can readily adapt any number of data processor structuring formats (e.g. text file or database) in order to obtain computer readable media having recorded thereon the nucleotide sequence information of the present invention.
By providing the nucleotide sequence of SEQ ID NO: 1-SEQ ID NO: 14103, a fragment thereof, or a nucleotide sequence at least about 99.5% identical to SEQ ID NO: 1-SEQ ID NO: 14103 in computer readable form, a person skilled in the art can routinely access the coding sequence information for a variety of purposes. Computer software is publicly available which allows a person skilled in the art to access sequence information provided in a computer readable media. Examples of such computer software include programs of the xe2x80x9cStaden Packagexe2x80x9d, xe2x80x9cDNA Starxe2x80x9d, xe2x80x9cMacVectorxe2x80x9d, GCG xe2x80x9cWisconsin Packagexe2x80x9d (Genetics Computer Group, Madison, Wis.) and xe2x80x9cNCBI Toolboxxe2x80x9d (National Center For Biotechnology Information). Suitable programs are described, for example, in Martin J. Bishop, ed., Guide to Human Genome Computing, 2d Edition, Academic Press, San Diego, Calif. (1998); and Leonard F. Peruski, Jr., and Anne Harwood Peruski, The Internet and the New Biology: Tools for Genomic and Molecular Research, American Society for Microbiology, Washington, D.C. (1997).
Computer algorithms enable the identification of C. albicans open reading frames (ORFs) within SEQ ID NO: 1-SEQ ID NO: 14103 which contain homology to ORFs or proteins from other organisms. Examples of such similarity-search algorithms include the BLAST [Altschul et al., J. Mol. Biol. 215:403-410 (1990)] and Smith-Waterman [Smith and Waterman (1981) Advances in Applied Mathematics, 2:482-489] search algorithms. Suitable search algorithms are described, for example, in Martin J. Bishop, ed., Guide to Human Genome Computing, 2d Edition, Academic Press, San Diego, Calif. (1998); and Leonard F. Peruski, Jr., and Anne Harwood Peruski, The Internet and the New Biology: Tools for Genomic and Molecular Research, American Society for Microbiology, Washington, D.C. (1997). Such algorithms are utilized on computer systems as exemplified below. The ORFs so identified represent protein encoding fragments within the C. albicans genome and are useful in producing commercially important proteins such as enzymes used in fermentation reactions and in the production of commercially useful metabolites.
The present invention further provides systems, particularly computer-based systems, which contain the sequence information described herein. Such systems are designed to identify commercially important fragments of the C. albicans genome. As used herein, xe2x80x9ca computer-based systemxe2x80x9d refers to the hardware means, software means, and data storage means used to analyze the nucleotide sequence information of the present invention. The minimum hardware means of the computer-based systems of the present invention comprises a central processing unit (CPU), input means, output means, and data storage means. A person skilled in the art can readily appreciate that any one of the currently available computer-based systems is suitable for use in the present invention. The computer-based systems of the present invention comprise a data storage means having stored therein a nucleotide sequence of the present invention and the necessary hardware means and software means for supporting and implementing a search means. As used herein, xe2x80x9cdata storage meansxe2x80x9d refers to memory which can store nucleotide sequence information of the present invention, or a memory access means which can access manufactures having recorded thereon the nucleotide sequence information of the present invention.
As used herein, xe2x80x9csearch meansxe2x80x9d refers to one or more programs which are implemented on the computer-based system to compare a target sequence or target structural motif with the sequence information stored within the data storage means. Search means are used to identify fragments or regions of the C. albicans genome which are similar to, or xe2x80x9cmatchxe2x80x9d, a particular target sequence or target motif. A variety of known algorithms are known in the art and have been disclosed publicly, and a variety of commercially available software for conducting homology-based similarity searches are available and can be used in the computer-based systems of the present invention. Examples of such software include, but are not limited to, FASTA (GCG Wisconsin Package), Bic_SW (Compugen Bioccelerator), BLASTN2, BLASTP2, BLASTX2 (NCBI) and Motifs (GCG). Suitable software programs are described, for example, in Martin J. Bishop, ed., Guide to Human Genome Computing, 2d Edition, Academic Press, San Diego, Calif. (1998); and Leonard F. Peruski, Jr., and Anne Harwood Peruski, The Internet and the New Biology: Tools for Genomic and Molecular Research, American Society for Microbiology, Washington, D.C. (1997). A person skilled in the art will readily recognize that any one of the available algorithms or implementing software packages for conducting homology searches can be adapted for use in the present computer-based systems.
As used herein, a xe2x80x9ctarget sequencexe2x80x9d can be any DNA or amino acid sequence of six or more nucleotides or two or more amino acids. A person skilled in the art can readily recognize that the longer a target sequence is, the less likely a target sequence will be present as a random occurrence in the database. The most preferred sequence length of a target sequence is from about 10 to 100 amino acids or from about 30 to 300 nucleotide residues. However, it is well recognized that many genes are longer than 500 amino acids, or 1.5 kb in length, and that commercially important fragments of the C. albicans genome, such as sequence fragments involved in gene expression and protein processing, will often be shorter than 30 nucleotides.
As used herein, xe2x80x9ca target structural motif,xe2x80x9d or xe2x80x9ctarget motif,xe2x80x9d refers to any rationally selected sequence or combination of sequences in which the sequence(s) are chosen based on a specific functional domain or three-dimensional configuration which is formed upon the folding of the target polypeptide. There is a variety of target motifs known in the art. Protein target motifs include, but are not limited to, enzymatic active sites, membrane-spanning regions, and signal sequences. Nucleic acid target motifs include, but are not limited to, promoter sequences, hairpin structures and inducible expression elements (protein binding sequences).
A variety of structural formats for the input and output means can be used to input and output the information in the computer-based systems of the present invention. A preferred format for an output means ranks fragments of the C. albicans genome possessing varying degrees of homology to the target sequence or target motif. Such presentation provides a person skilled in the art with a ranking of sequences which contain various amounts of the target sequence or target motif and identifies the degree of homology contained in the identified fragment.
A variety of comparing means can be used to compare a target sequence or target motif with the data storage means to identify sequence fragments of the C. albicans genome. In the present examples, implementing software which implement the BLASTP2 and bic_SW algorithms (Altschul et al., J Mol. Biol. 215:403-410 (1990); Compugen Biocellerator) was used to identify open reading frames within the C. albicans genome. A person skilled in the art can readily recognize that any one of the publicly available homology search programs can be used as the search means for the computer-based systems of the present invention. Suitable programs are described, for example, in Martin J. Bishop, ed., Guide to Human Genome Computing, 2d Edition, Academic Press, San Diego, Calif. (1998); and Leonard F. Peruski, Jr., and Anne Harwood Peruski, The Internet and the New Biology: Tools for Genomic and Molecular Research, American Society for Microbiology, Washington, D.C. (1997).
The invention features C. albicans polypeptides, preferably a substantially pure preparation of an C. albicans polypeptide, or a recombinant C. albicans polypeptide. In preferred embodiments: the polypeptide has biological activity; the polypeptide has an amino acid sequence at least about 60%, 70%, 80%, 90%, 95%, 98%, or 99% identical to an amino acid sequence of the invention contained in the Sequence Listing, preferably it has about 65% sequence identity with an amino acid sequence of the invention contained in the Sequence Listing, and most preferably it has about 92% to about 99% sequence identity with an amino acid sequence of the invention contained in the Sequence Listing; the polypeptide has an amino acid sequence essentially the same as an amino acid sequence of the invention contained in the Sequence Listing; the polypeptide is at least about 5, 10, 20, 50, 100, or 150 amino acid residues in length; the polypeptide includes at least about 5, preferably at least about 10, more preferably at least about 20, more preferably at least about 50, 100, or 150 contiguous amino acid residues of the invention contained in the Sequence Listing. In yet another preferred embodiment, the amino acid sequence which differs in sequence identity by about 7% to about 8% from the C. albicans amino acid sequences of the invention contained in the Sequence Listing is also encompassed by the invention.
In preferred embodiments: the C. albicans polypeptide is encoded by a nucleic acid of the invention contained in the Sequence Listing, or by a nucleic acid having at least about 60%, 70%, 80%, 90%, 95%, 98%, or 99% homology with a nucleic acid of the invention contained in the Sequence Listing.
In a preferred embodiment, the subject C. albicans polypeptide differs in amino acid sequence at about 1, 2, 3, 5, 10 or more residues from a sequence of the invention contained in the Sequence Listing. The differences, however, are such that the C. albicans polypeptide exhibits an C. albicans biological activity, e.g., the C. albicans polypeptide retains a biological activity of a naturally occurring C. albicans enzyme.
In preferred embodiments, the polypeptide includes all or a fragment of an amino acid sequence of the invention contained in the Sequence Listing; fused, in reading frame, to additional amino acid residues, preferably to residues encoded by genomic DNA 5xe2x80x2 or 3xe2x80x2 to the genomic DNA which encodes a sequence of the invention contained in the Sequence Listing.
In yet other preferred embodiments, the C. albicans polypeptide is a recombinant fusion protein having a first C. albicans polypeptide portion and a second polypeptide portion, e.g., a second polypeptide portion having an amino acid sequence unrelated to C. albicans. The second polypeptide portion can be, e.g., any of glutathione-S-transferase, a DNA binding domain, or a polymerase activating domain. In preferred embodiment the fusion protein can be used in a two-hybrid assay.
Polypeptides of the invention include those which arise as a result of alternative transcription events, alternative RNA splicing events, and alternative translational and postranslational events.
In a preferred embodiment, the encoded C. albicans polypeptide differs (e.g., by amino acid substitution, addition or deletion of at least one amino acid residue) in amino acid sequence at about 1, 2, 3, 5, 10 or more residues, from a sequence of the invention contained in the Sequence Listing. The differences, however, are such that: the C. albicans encoded polypeptide exhibits a C. albicans biological activity, e.g., the encoded C. albicans enzyme retains a biological activity of a naturally occurring C. albicans. 
In preferred embodiments, the encoded polypeptide includes all or a fragment of an amino acid sequence of the invention contained in the Sequence Listing; fused, in reading frame, to additional amino acid residues, preferably to residues encoded by genomic DNA 5xe2x80x2 or 3xe2x80x2 to the genomic DNA which encodes a sequence of the invention contained in the Sequence Listing.
The C. albicans strain from which the nucleotide sequences have been sequenced is strain SC5314, a clinical isolate which was originally obtained from a patient with disseminated candidiasis.
Included in the invention are: allelic variations; natural mutants; induced mutants; proteins encoded by DNA that hybridize under high or low stringency conditions to a nucleic acid which encodes a polypeptide of the invention contained in the Sequence Listing (for definitions of high and low stringency see Current Protocols in Molecular Biology, John Wiley and Sons, New York, 1989, 6.3.1-6.3.6, hereby incorporated by reference); and, polypeptides specifically bound by antisera to C. albicans polypeptides, especially by antisera to an active site or binding domain of C. albicans polypeptide. The invention also includes fragments, preferably biologically active fragments. These and other polypeptides are also referred to herein as C. albicans polypeptide analogs or variants.
The invention further provides nucleic acids, e.g., RNA or DNA, encoding a polypeptide of the invention. This includes double stranded nucleic acids as well as coding and antisense single strands.
In preferred embodiments, the subject C. albicans nucleic acid will include a transcriptional regulatory sequence, e.g. at least one of a transcriptional promoter or transcriptional enhancer sequence, operably linked to the C. albicans gene sequence, e.g., to render the C. albicans gene sequence suitable for expression in a recombinant host cell.
In yet a further preferred embodiment, the nucleic acid which encodes an C. albicans polypeptide of the invention, hybridizes under stringent conditions to a nucleic acid probe corresponding to at least about 8 consecutive nucleotides of the invention contained in the Sequence Listing; more preferably to at least about 12 consecutive nucleotides of the invention contained in the Sequence Listing; more preferably to at least about 20 consecutive nucleotides of the invention contained in the Sequence Listing; more preferably to at least about 40 consecutive nucleotides of the invention contained in the Sequence Listing.
In another aspect, the invention provides a substantially pure nucleic acid having a nucleotide sequence which encodes an C. albicans polypeptide. In preferred embodiments: the encoded polypeptide has biological activity; the encoded polypeptide has an amino acid sequence at least about 60%, 70%, 80%, 90%, 95%, 98%, or 99% homologous to an amino acid sequence of the invention contained in the Sequence Listing; the encoded polypeptide has an amino acid sequence essentially the same as an amino acid sequence of the invention contained in the Sequence Listing; the encoded polypeptide is at least about 5, 10, 20, 50, 100, or 150 amino acids in length; the encoded polypeptide comprises at least about 5, preferably at least about 10, more preferably at least about 20, more preferably at least about 50, 100, or 150 contiguous amino acids of the invention contained in the Sequence Listing.
In another aspect, the invention encompasses: a vector including a nucleic acid which encodes an C. albicans polypeptide or an C. albicans polypeptide variant as described herein; a host cell transfected with the vector; and a method of producing a recombinant C. albicans polypeptide or C. albicans polypeptide variant; including culturing the cell, e.g., in a cell culture medium, and isolating an C. albicans or C. albicans polypeptide variant, e.g., from the cell or from the cell culture medium.
One embodiment of the invention is directed to substantially isolated nucleic acids. Nucleic acids of the invention include sequences comprising at least about 8 nucleotides in length, more preferably at least about 12 nucleotides in length, even more preferably at least about 15-20 nucleotides in length, that correspond to a subsequence of any one of SEQ ID NO: 1-SEQ ID NO: 14103 or complements thereof. Alternatively, the nucleic acids comprise sequences contained within any ORF (open reading frame), including a complete protein-coding sequence, of which any of SEQ ID NO: 1-SEQ ID NO: 14103 forms a part. The invention encompasses sequence-conservative variants and function-conservative variants of these sequences. The nucleic acids may be DNA, RNA, DNA/RNA duplexes, protein-nucleic acid (PNA), or derivatives thereof.
In another aspect, the invention features, a purified recombinant nucleic acid having at least about 50%, 60%, 70%, 80%, 90%, 95%, 98%, or 99% homology with a sequence of the invention contained in the Sequence Listing.
The invention also encompasses recombinant DNA (including DNA cloning and expression vectors) comprising these C. albicans-derived sequences; host cells comprising such DNA, including fungal, bacterial, yeast, plant, insect, and mammalian host cells; and methods for producing expression products comprising RNA and polypeptides encoded by the C. albicans sequences. These methods are carried out by incubating a host cell comprising a C. albicans-derived nucleic acid sequence under conditions in which the sequence is expressed. The host cell may be native or recombinant. The polypeptides can be obtained by (a) harvesting the incubated cells to produce a cell fraction and a medium fraction; and (b) recovering the C. albicans polypeptide from the cell fraction, the medium fraction, or both. The polypeptides can also be made by in vitro translation.
In another aspect, the invention features nucleic acids capable of binding mRNA of C. albicans. Such nucleic acid is capable of acting as antisense nucleic acid to control the translation of mRNA of C. albicans. A further aspect features a nucleic acid which is capable of binding specifically to a C. albicans nucleic acid. These nucleic acids are also referred to herein as complements and have utility as probes and as capture reagents.
In another aspect, the invention features an expression system comprising an open reading frame corresponding to C. albicans nucleic acid. The nucleic acid further comprises a control sequence compatible with an intended host. The expression system is useful for making polypeptides corresponding to C. albicans nucleic acid.
In another aspect, the invention encompasses: a vector including a nucleic acid which encodes a C. albicans polypeptide or a C. albicans polypeptide variant as described herein; a host cell transfected with the vector; and a method of producing a recombinant C. albicans polypeptide or C. albicans polypeptide variant; including culturing the cell, e.g., in a cell culture medium, and isolating the C. albicans or C. albicans polypeptide variant, e.g., from the cell or from the cell culture medium.
In yet another embodiment of the invention encompasses reagents for detecting fungal infection, including C. albicans infection, which comprise at least one C. albicans-derived nucleic acid defined by any one of SEQ ID NO: 1-SEQ ID NO: 14103, or sequence-conservative or function-conservative variants thereof. Alternatively, the diagnostic reagents comprise polypeptide sequences that are contained within any open reading frames (ORFs), including complete protein-coding sequences, contained within any of SEQ ID NO: 1-SEQ ID NO: 14103, or polypeptide sequences contained within any of SEQ ID NO: 14104-SEQ ID NO: 28206, or polypeptides of which any of the above sequences forms a part, or antibodies directed against any of the above peptide sequences or function-conservative variants and/or fragments thereof.
The invention further provides antibodies, preferably monoclonal antibodies, which specifically bind to the polypeptides of the invention. Methods are also provided for producing antibodies in a host animal. The methods of the invention comprise immunizing an animal with at least one C. albicans-derived immunogenic component, wherein the immunogenic component comprises one or more of the polypeptides encoded by any one of SEQ ID NO: 1-SEQ ID NO: 14103 or sequence-conservative or function-conservative variants thereof; or polypeptides that are contained within any ORFs, including complete protein-coding sequences, of which any of SEQ ID NO: 1-SEQ ID NO: 14103 forms a part; or polypeptide sequences contained within any of SEQ ID NO: 14104-SEQ ID NO: 28206; or polypeptides of which any of SEQ ID NO: 14104-SEQ ID NO: 28206 forms a part. Host animals include any warm blooded animal, including without limitation mammals and birds. Such antibodies have utility as reagents for immunoassays to evaluate the abundance and distribution of C. albicans-specific antigens.
In yet another aspect, the invention provides diagnostic methods for detecting C. albicans antigenic components or anti-C. albicans antibodies in a sample. C. albicans antigenic components are detected by a process comprising: (i) contacting a sample suspected to contain a fungal antigenic component with a fungal-specific antibody, under conditions in which a stable antigen-antibody complex can form between the antibody and fungal antigenic components in the sample; and (ii) detecting any antigen-antibody complex formed in step (i), wherein detection of an antigen-antibody complex indicates the presence of at least one fungal antigenic component in the sample. In different embodiments of this method, the antibodies used are directed against a sequence encoded by any of SEQ ID NO: 1-SEQ ID NO: 14103 or sequence-conservative or function-conservative variants thereof, or against a polypeptide sequence contained in any of SEQ ID NO: 14104-SEQ ID NO: 28206 or function-conservative variants thereof.
In yet another aspect, the invention provides a method for detecting antifungal-specific antibodies in a sample, which comprises: (i) contacting a sample suspected to contain antifungal-specific antibodies with a C. albicans antigenic component, under conditions in which a stable antigen-antibody complex can form between the C. albicans antigenic component and antifungal antibodies in the sample; and (ii) detecting any antigen-antibody complex formed in step (i), wherein detection of an antigen-antibody complex indicates the presence of antifungal antibodies in the sample. In different embodiments of this method, the antigenic component is encoded by a sequence contained in any of SEQ ID NO: 1-SEQ ID NO: 14103 or sequence-conservative and function-conservative variants thereof, or is a polypeptide sequence contained in any of SEQ ID NO: 14104-SEQ ID NO: 28206 or function-conservative variants thereof.
In another aspect, the invention features a method of generating vaccines for immunizing an individual against C. albicans. The method includes: immunizing a subject with a C. albicans polypeptide, e.g., a surface or secreted polypeptide, or a combination of such peptides or active portion(s) thereof, and a pharmaceutically acceptable carrier. Such vaccines have therapeutic and prophylactic utilities.
In another aspect, the invention features a method of evaluating a compound, e.g. a polypeptide, e.g., a fragment of a host cell polypeptide, for the ability to bind a C. albicans polypeptide. The method includes: contacting the candidate compound with a C. albicans polypeptide and determining if the compound binds or otherwise interacts with an C. albicans polypeptide. Compounds which bind C. albicans are candidates as activators or inhibitors of the fungal life cycle. These assays can be performed in vitro or in vivo.
In another aspect, the invention features a method of evaluating a compound, e.g. a polypeptide, e.g., a fragment of a host cell polypeptide, for the ability to bind an C. albicans nucleic acid, e.g., DNA or RNA. The method includes: contacting the candidate compound with a C. albicans nucleic acid and determining if the compound binds or otherwise interacts with a C. albicans polypeptide. Compounds which bind C. albicans are candidates as activators or inhibitors of the fungal life cycle. These assays can be performed in vitro or in vivo.
A particularly preferred embodiment of the invention is directed to a method of screening test compounds for anti-fungal activity, which method comprises: selecting as a target a fungal specific sequence, which sequence is essential to the viability of a fungal species; contacting a test compound with said target sequence; and selecting those test compounds which bind to said target sequence as potential anti-fungal candidates. In one embodiment, the target sequence selected is specific to a single species, or even a single strain, i.e., the C. albicans strain SC5314. In a second embodiment, the target sequence is common to at least two species of fungi. In a third embodiment, the target sequence is common to a family of fungi. The target sequence may be a nucleic acid sequence or a polypeptide sequence. Methods employing sequences common to more than one species of microorganism may be used to screen candidates for broad spectrum anti-fungal activity.
The invention also provides methods for preventing or treating disease caused by certain fungi, including C. albicans, which are carried out by administering to an animal in need of such treatment, in particular a warm-blooded vertebrate, including but not limited to birds and mammals, a compound that specifically inhibits or interferes with the function of a fungal polypeptide or nucleic acid. In a particularly preferred embodiment, the mammal to be treated is human.